1. Field of the Invention
This invention relates to a cold/hot water discharging apparatus which discharges alternately hot water having a high temperature and hot water having a low temperature from a discharge portion so as to obtain a massage effect. More particularly, the present invention relates to a cold/hot water discharging apparatus which switches and regulates alternately hot water of a predetermined temperature supplied from a hot water supply source to mixed hot water having a high temperature and to mixed hot water having a low temperature by a cold/hot water mixing tap and supplies them to a discharge portion.
2. Description of the Prior Art
Conventional cold/hot water discharging apparatuses can be classified into a system which switches alternately the temperature of hot water supplied from a hot water supply machine to high and low temperatures and supplies directly hot water supplied from this hot water supply machine to a discharge portion, and a system which mixes high temperature hot water supplied from a hot water supply machine with cold water by a cold/hot water mixing tap to obtain mixed hot water having a predetermined temperature and supplies alternately this mixed hot water and cold water supplied from a feed water source to the discharge portion through a valve capable of alternately switching the inflow sides.
However, the inventors of the present invention developed a cold/hot water discharging apparatus of a novel system which is entirely different from the prior art systems described above.
Namely, the cold/hot water discharging apparatus in accordance with the present invention is of the system wherein hot water of a predetermined temperature supplied from a hot water supply machine is switched and regulated alternately to mixed hot water of a high temperature and mixed hot water of a low temperature by a cold/hot water mixing tap and supplied to a discharge portion. More definitely, in the apparatus of the present invention, a valve of the cold/hot water mixing tap is driven by a motor and is controlled in such a manner as to reciprocate between a position at which high temperature hot water is to be discharged and a position at which low temperature hot water is to be discharged in a predetermined period.
In this cold/hot water discharging apparatus, the temperatures and periods of low temperature hot water and high temperature hot water are controlled by the speed of the valve and this speed is determined by the difference between an actual temperature and a target temperature and by a gain.
However, if the gain is constant in the cold/hot water discharging apparatus described above, there is the problem in that a stable curve of output hot water having a short cold/hot water discharge period cannot be obtained at the time of pressure fluctuation, and so forth.
For, an optimum gain varies with the temperatures of cold/hot water and with the pressure.